Wednesday, February 25, 2009

There are a few faces which, when we see them depicted anywhere, need no accompanying text to say who they are. Einstein and Darwin are two outstanding examples. They are giants of science, and even more, they are giants of general culture, whose work has wrought fundamental changes in the way the universe is understood and viewed well beyond their own sciences of biology and physics.

These remarks are indisputably true, but a slightly misleading implication of them has to be guarded against. This is that without the two men in question, those same advances would not have been made. That would be a mistaken view. Science is a co-operative enterprise, and every advance depends upon those made beforehand, both in theory and in the practicalities of research. Had Darwin not lived to publish his Origin of Species its insights would have emerged anyway following the work of Alfred Russel Wallace and other naturalists. This is illustrated by the fact that when T. H. Huxley first encountered Darwin’s views he said to himself, “How stupid not to have seen that!”

Many before Darwin had proposed the ideas of evolution and the mutability of species; the great age of the earth was well understood; the convergence of lessons from geology, the fossil record, natural history, and the selective breeding of crops and domestic animals, which Darwin added to his own observations and reasonings derived from the Beagle voyage, would have been effected by others sooner rather than later, for these ideas were being energetically pursued. So it is the central ideas of evolutionary biology, for which Darwin was the prime convener, that have the impact that I shall sketch here, using “Darwinism” and “evolutionary theory” as a shorthand for this. Here too, though, a prefatory note is in order. Darwin saw that all living things have descended from a common ancestor by natural selection.

In identifying natural selection as the mechanism by which speciation occurs, he gave the first great impetus to the new world view which has followed, for he had identified a mechanism which applies in many other respects too, well beyond the biological sciences. It (natural selection) is a mechanism which economically describes how complexity arises from simpler elements through modifications selected by pressures of various kinds. From individual learning to social change to the development of technologies such as steam engines and computers, the pattern is visible and explanatorily powerful. As a result the concept of evolution has come to be deployed – sometimes controversially – outside biology, influencing thought in other natural sciences and in the social sciences, the humanities, philosophy and literature.

Familiarly, Darwinism itself had to wait until recognition of Gregor Mendel’s work on peas had given rise to an understanding of genes and their role, and then for the discipline of population genetics to develop, for what Julian Huxley called the “new synthesis” in evolutionary biology to emerge. This “new synthesis” is the standard view, and serves as the central organising principle of all the biological sciences. When I talk of “Darwinism” or “evolutionary theory” here, I mean this.

We can take for granted the transformative effect of evolutionary theory on the biological sciences, but as just suggested, the impact goes much further. The first and most obvious example is the impact on traditional views of humankind and its place in the universe. A first revolution in this respect had occurred when the Copernican view about our planet’s position in the solar system challenged the idea that humanity is the pinnacle of creation at the centre of the universe. It is hard now to appreciate the blow this gave not just to theology but to human amour propre. It was nevertheless still possible for many to continue believing that the earth and its inhabitants were created by an interested intelligent agency with some purpose for them in mind. But Darwin’s discoveries took the displacement of humanity from some kind of cosmic pole position further, by placing it squarely in nature, and describing nature itself as a realm of nonpurposive forces and circumstances in which, through vast tracts of time and with enormous wastage, biological complexity emerges from simpler elements and structures. There is neither room nor need here for the idea of an interested purposive agency or deity. Darwin was of course fully aware of this implication, and delayed general publication of his findings partly for this reason. Reception of Darwin’s ideas in his own day was very mixed, with some being variously frightened or outraged by them and others welcoming them.

His theory was widely misunderstood as the claim that human beings have descended from monkeys, and Darwin himself was caricatured as an orangutan. The spectrum of religious views was broad enough for some clerics to think that evolution was consistent with theology; the Reverend Charles Kingsley wrote to Darwin to commend his work, and Darwin included a reference to Kingsley’s endorsement in the third edition of the Origin, in an effort to placate some of those who accused him of destroying morality by attacking religion.

Whereas Darwin’s discoveries and those in geology and palaeology refuted religious views based on a six-day creation and the fixity of species, some religious apologists tried to articulate a view of “theistic creation”, in which a deity sets the evolutionary process in motion and perhaps occasionally puts a hand on the tiller to ensure “progress” towards the emergence of “higher forms of life”. But this too Darwin rejected, as he shows in his autobiographical writings and correspondence. The main argument against “theistic evolution” is that the involvement of an agency in the evolutionary process is unnecessary and redundant.

For Darwin the compelling reason was what philosophers call “the problem of evil”: that nature is so wasteful and so full of suffering that the idea it should even be countenanced, still less deliberately created, by an agency competent to do otherwise, was repugnant. He had, he tells us in his autobiographical notes, given up Christianity early; he had become a complete “agnostic” by the time the Origin was written. In the passage of the autobiographical notes where Darwin recounts these points – a passage which in earlier editions was omitted at the request of his widow as too painful to her sensibilities – he directly describes himself as an agnostic, and indirectly as a sceptic. He wrote, “Nothing is more remarkable than the spread of scepticism or rationalism during the latter half of my life. Before I was engaged to be married, my father advised me to conceal carefully my doubts, for he said that he had known extreme misery thus caused with married persons…[he] added that he had known during his whole long life only three women who were sceptics…[though] he had to own with respect to one of them, his sister-inlaw Kitty Wedgwood, that he had no good evidence, only the vaguest hints, aided by the conviction that so clearsighted a woman could not be a believer.”

Darwin was clear-sighted, as his scientific work vastly shows; the implication that he was “not a believer” (a stronger claim than that he was “merely” agnostic) follows. His use of the word “agnostic,” coined by his friend and colleague T. H. Huxley in the first battles of the “Darwin wars” that followed publication of the Origin, should not be allowed to mislead. Even today in many parts of the world the word “atheist” has the resonance for some of “murderer” or “paedophile”; this was all the more so in the nineteenth century; it was a term of malediction. “Sceptic”, “rationalist” and “agnostic” did duty instead.

Religious apologists, clutching at straws, prefer it when people self-describe as “agnostic” because they hope that it leaves open a smidgeon of possibility that there might be supernatural agencies in the universe.

Manifestly, that is not what someone “too clear-sighted to be a believer” would intend by using the term. The expression “the Darwin wars” could be used to refer to the continuing effort mounted by opponents of Darwinian biology to cling to creationist views, including the more sophisticated (and sophistical) avatar of these views as “intelligent design theory”, a story that runs through the Scopes trial of 1925 to the present day, sustained by wellorganised and well-funded religious lobbies principally in the United States.

But the phrase “the Darwin wars” has come to denote a different aspect of the impact of Darwinism, relating to the use made of the concept of evolution in the social sciences, and specifically in the new fields known as socio-biology and evolutionary psychology. These have provoked a storm of controversy, their critics pointing out that the effort to explain society and psychology in purely evolutionary terms is too reductive, because it ignores the influence of culture, learning, and the concomitant transmission of values and beliefs, together with the feedback mechanisms that these factors themselves involve in prompting further change. The quarrel about the limits of application of evolutionary theory outside biology has often been a vituperative one, with Stephen Jay Gould calling evolutionary psychology a form of “fundamentalist Darwinism” and therefore “foolish,” “fatuous,” “pathetic” and “egregiously simplistic.” He also locked horns with Daniel Dennett and others over his own reformulation of Darwinian theory in terms of “punctuated equilibrium”. While these arguments have proceeded, other social scientists have been disturbed by the fact that in his Descent of Man Darwin himself gave some ground for the extrapolations of evolutionary theory into talk of race and eugenics that followed, in the hands of Herbert Spencer (from whom Darwin himself borrowed the term “survival of the fittest” in later editions of the Origin), Francis Galton, and eventually the Nazis and others. Here the point to be made is that a theory as powerful as Darwinism inevitably gets dragged through all sorts of bushes into neighbouring fields, too many of them inappropriate; and obviously enough the failure or misapplication of the theory in those fields does not in any way infirm the theory in its home sphere.

In line with this thought, it remains that the greatest impact of Darwinism is in biology and such related fields as agriculture, medicine and neuroscience, from which some of the greatest changes to life and the future are already flowing. When the “Darwin wars” over the insights offered by evolutionary theory into psychology and society have calmed down, there will doubtless be found much of value there too. Although evolutionary scientists themselves continue to investigate the fine details of aspects of evolution – the significance of factors such as genetic drift and catastrophe as well as chance mutation, for example – the fact is that evolution is a fact, not a speculative hypothesis.

Opponents of evolutionary theory, principally the creationist lobbies, try to insist on the point that evolutionary theory is a theory, as if doing so introduced a significant element of doubt. This is a misunderstanding (and a wilful one) about the concept of a theory in science. Unlike hypotheses, which are suggestions to be tested and scrutinized, scientific theories such as Newton’s theory of gravitation and Einstein’s general relativity are powerfully supported by evidence and the success of their application. They are facts, not suppositions, even if we can expect to refine and improve our understanding of them, and discover more about their implications, as our enquiries continue. Evolution is a fact, fully and overwhelmingly supported by evidence and by every consequence it supports. One example will suffice: we test new medications on guinea pigs rather than ants because the former are genetically closer to humans than the latter. This simple point is explained by the fact that the common ancestor of guinea pigs and humans is more recent than the common ancestor of guinea pigs, ants and humans.

The power of the theory explains why efforts, often successful, to apply it in fields other than biology are so attractive. Underlying it is the idea that complexity arises from simplicity without purposes or consciousness. Here is the key of the Darwinian revolution: beforehand it was thought that complex things can only be brought about by yet more complex things; there was no grasp of how matters could be otherwise.

That is why even after Copernicus religious views persisted. But “the blind watchmaker,” as Richard Dawkins called natural selection in contradistinction to Paley’s watchmaker analogy for purposive design in nature, is fully competent to produce the millions of life forms – 90 percent of them now extinct – that the planet has so far seen, nothing else required.

One thing is certain: evolutionary theory has changed the entire framework of thinking about the world and mankind in it, and there is no going back: Darwin’s life and work marks a watershed, and we are just beginning our journey into its further side.